The present invention relates generally to the field of occupant detection. Specifically, the present invention is directed to a system and method of identifying whether a passenger seat is empty, or whether an object or occupant is in the seat. The occupant, for example, could be a person seated directly on the seat or a child in a child seat.
There are many existing systems that employ sensors to detect and classify an occupant located in a passenger seat of a vehicle. Weight sensors, vision sensors, pressure sensors, capacitive sensors are examples of some devices that may be used in occupant detection systems.
The general objective of the classification systems described above, is to determine whether there is an occupant present in a vehicle seat. In turn, information collected by the sensors may be used by a vehicle safety restraint system to determine whether to activate certain devices to protect actual vehicle occupants. Alternatively, the information collected by the sensors could be used to warn occupants that their seat belt is not buckled. In addition, the system described above could be used to identify occupant presence in the front passenger positions or in the passenger positions in seating rows rear of the driver.
Generally, conventional systems do not produce consistent results. These systems have difficulty consistently identifying and accurately monitoring empty seat conditions. For example, typical systems have difficulty discerning an empty seat from a seat that is occupied by a child seat.
Measurement based on the vertical force applied on a vehicle seat may also produce inconsistent results because an occupied child seat may cause the pressure distribution and total force on the seat to be very low. As a result, it may be difficult to discern whether an occupant is present in the vehicle seat (e.g., a 10 pound child in an 8 pound child seat spread across much of the seat bottom).
Thus, a more sensitive system for detecting the presence of an object or occupant in a vehicle seat is needed.